Game concept
Courtier
The game also links it as Courtiers.
From the game's encyclopedia
A Courtier is an Unlanded character who serves a Ruler in their Court.
Courtiers can:
• Serve as Councillors
• Serve in Court Positions
• Serve in Armies as Commanders or Knights
• Become their Ruler's Vassal if granted a Title
• Let their Ruler press their Claims in War
Adventurers have Followers instead of Courtiers — they serve the same role, albeit generally smellier and with more mud.
The game's text for patch 1.20.1.2. Words in blue are entries of the encyclopedia: hover one to read it, as in the game.
Courtier is an entry of Crusader Kings III's in-game encyclopedia. The game explains it: "A Courtier is an Unlanded character who serves a Ruler in their Court." The game also links it as Courtiers. Patch 1.20.1.2, from game/common/game_concepts/00_game_concepts.txt and game/localization/english/game_concepts_l_english.yml.
Source: game/common/game_concepts/00_game_concepts.txt, game/localization/english/game_concepts_l_english.yml and the English localisation, Crusader Kings III 1.20.1.2.